LB7 1400 Mile Road Trip Feed Back

[Hardtailxxx]

I made a road trip recently and wanted to post my info to get a new thread started on open road feed back. Here goes,,,$.02

The truck is a 2003 GMC 4x4, CC, SB, 2500HD W/ D/A with 35" tires, 3:73 gearing, Triple Dog tuner, 4" intake, 4" open exhaust, among other mods...


The trip was 1200 miles along the southeastern U.S. with my wife and my 2 1/2 year old daughter to see some family. The truck was loaded only with the three of us, a couple of suitcases, and a full tank of the great stuff known as ULSD (Thanks to the EPA for that one). So as we started to leave I set my Triple dog to the tow/economy tune, gave my daughter a bag of goldfish crackers, and away we went. The local temp was about 65 degrees when we left, with clear blue skies and would stay this way with temps in the 65-85 range along the way. For most of the trip the surrounding terrain was smooth, flat roadway with the occasional slight uphill and downhill grade as is well known for most of the southeast. I made notes from the start, midway, and near the end of our trip then averaged the 3 sets of readings together for a more real world report.

The averages over 1200 miles were recorded during open cruising stretches as follows:

Speed: 78 mph
Tach: 2200 rpm
Engine Temp: 185 deg
Tranny Temp: 150 deg
Oil Pressure: 63 psi
Voltage: 16 volts
Boost: 5 psi
EGT: 575 deg

Average fuel mileage for the trip: 29 mpg (1226 miles total, with 42 gallons of fuel used)

 

[partsguy662]

I made a road trip recently and wanted to post my info to get a new thread started on open road feed back. Here goes,,,$.02

The truck is a 2003 GMC 4x4, CC, SB, 2500HD W/ D/A with 35" tires, 3:42 gearing, Triple Dog tuner, 4" intake, 4" open exhaust, among other things.


The trip was 1200 miles along the southeastern U.S. with my wife and my 2 1/2 year old daughter to see some family. The truck was loaded only with the three of us, a couple of suitcases, and a full tank of the great stuff known as ULSD (Thanks to the EPA). So as we started to leave I set my Triple dog to the tow/economy tune, gave my daughter a bag of goldfish crackers, and away we went. The local temp was about 65 degrees when we left, with clear blue skies and would stay this way with temps in the 65-85 range along the way. For most of the trip the surrounding terrain was smooth, flat roadway with the occasional slight uphill and downhill grade as is well known for most of the southeast. I made notes from the start, midway, and near the end of our trip then averaged the 3 sets of readings together for a more real world report.

The averages over 1200 miles were recorded during open cruising stretches as follows:

Speed: 78 mph
Tach: 2200 rpm
Engine Temp: 185 deg
Tranny Temp: 150 deg
Oil Pressure: 63 psi
Voltage: 16 volts
Boost: 5 psi
EGT: 575 deg

Average fuel mileage for the trip: 29 mpg (1226 miles total, with 42 gallons of fuel used)

I think your speedometer is off....
3.42 gears? how did that happen?

 

[JD Dearden]

I think your speedometer is off....
3.42 gears? how did that happen?

Ya buddy I have 3.73 gears with 22.5" rims and tall tires and I run at 2400 rpm's at 80mph.

 

[moss]

i woulda thought that the rpm would of been a little lower with 35" tires. my 32.5" tires are about 1900 rpm at 70 i do believe. will have to double check

 

[gunracer1]

i suggest you keep that truck for the rest of your life if it really gets that kind of miliage. but to tell you the truth i don't belive it. i have heard of some 24 mpg but that was few and far between. i suggest you quite looking at the over head and find the other receipt for the other tank of fuel you missed counting. and i have a 4 door 4x4 dura max.

 

[Mike L.]

You can't even get that kind of mileage off a cliff.